Capabilities of a particular wireless ATM network to offer guaranteed quality of service in a manner specified for ATM are characterized in this thesis. A software architecture aiming to provide a feasible videoconferencing service in this constrained environment, utilizing adaptation schemes, is presented.Telecommunication networks conforming to the Broadband Integrated Services Digital Network (B-ISDN) concept are required to offer transmission services that agree to a negotiated traffic description for the whole connection lifetime. Quality of service guaranteeing is an essential function that this kind of a network is obliged to provide. -ATM technology implements this concept. Utilizing a fixed physical medium below the ATM protocol layer, it is able to offer transmission service with bounded transmission delay, delay variation, throughput and bit error rate. This is the very same requirement that is needed for audio and video transmission in interactive applications. Thus, fixed ATM offers a suitable basis for implementing, e.g., videoconferencing services. -The situation is less straightforward if the fixed physical layer is replaced with a wireless medium. The radio interface limits considerably the possibility to offer similar transmission services. The bit error rate, for instance, becomes notably higher in the wireless environment. Location of a mobile terminal relative to an access point, as well as obstacles between them affect the possibility of offering similar transmission services. During a handover, the service may not be available at all, which is also the case after the handover if existing connections in the new access point consume all its resources. -These examples reveal that the quality of transmission in wireless ATM is much worse than in its fixed counterpart. Furthermore, the service quality in wireless ATM may ,vary dynamically during the connection lifetime. Quality of service guaranteeing is no longer possible in a way specified for ATM. -Adaptation seems to be an accepted method to adjust applications to such environment. Adaptive applications lessen their resource usage when transmission service is partly or completely unavailable, being able to recover from this unavailability as well.